Safety device for overhead electric wires



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SAFETY DEVICE FOR OVERHEAD ELECTRIC WIRES.

SPECIFICATION forming part of Letters Patent No. 450,626, dated April 21, 1891.

Application letl January 30, 1891. Serial No. 379,718. (No model.)

To all whom it may concern:

Be it known that I, MAX KERSTEIN, a subject of the Emperor of Germany, residing in Boston, in the county of Suiifolk and State of Massachusetts, have invented an Improved Device for Automatically Insulating a'Broken lVire in an Electrical Circuit, of which the following' is a specification.

This is a.device intended for application to an electric wire, more particularly an electriclight wire, whereby on the accidental breakage of such wire the broken end will be instantly and automaticallyinsulated, thus rendering it harmless in case it should fall upon another Wire or any object or person, and it is intended as an improvement upon the invention described in my Letters Patent numbered 438,814, and granted October 2l, 1390,

to which reference is made.

The improvement consists, essentially, in the substitution for the cylindrical box A, lined with insulating material b, as described in said Letters Patent, of a pair of rods or wires made of conductive material and covered with insulating' material, said rods connecting a pair of metallic bars, all arranged as below described, and illustrated in the accompanying drawings, in Which-` Figure 1 is aside elevation of my improved device as applied to an electric-light wire. Fig. 2 is a longitudinal section of the same.

Fig. 3 is a longitudinal section of the device in the position assumed when the wire has become broken and is insulated by the operation of the device.

In Figs. l and 2 small portions are represented as broken out.

Similar letters of reference indicate corresponding parts.

A A represent two parallel Wires or rods of conductive material, and B B are metallic cross-bars. These wires A are rigidly secured in the cross-bar B and extend therefrom through openings B in the cross-bar B be.- ing held in said cross-bar by the nuts O on the threaded .ends ot said wires. The other ends of the wires A meet at A. The portions of the wires between the two cross-bars are covered with'insulating material d.

b Z1 are blocks or linings of insulation secured to the inner surfaces of the cross-pieces B B', respectively, and extending from the insulation on one wire A to that on the other. The cross-piece B is centrally Vperforated to receive a cylindrical block or piston D, of conductive material, which -lies normally in the position shown in Figs. l and 2, and is provided with a Ilan ge D', whereby it is prevented from 4being pulled entirely through said perforation. This block or piston is rigidly secured to the metallic rod E, whose inner end is secured to a head F and whose outer end is adapted to be secured to the electric Wire S. The head F is lined on its inner surface with the insulation d, and the portion of the rod or wire E between the insulation d and the block or piston D is covered with insulation e, while theouter portion is covered with insulation g. A spiral spring H lies between the head F and the cross-piece B. The headF and its insulation-lining d extend from the insulation. on one wire A to that on the other and are grooved at their ends, so as to tit over and slide upon said wires. The ends A of the Wires A are secured by means of the wire S to the insulator, say, on the supportingpole of an electric-light Wire, while the outer end ot the wire E is secured to the true electric wire S and makes a part of the circuit.

lVheu no breakage has occurred, thedevice is in the position shown in Fig. 2-that is, with the spring H contracted by the pulling of the wire E upon the head F, exactly as in thel Letters Patent above referred to the spring E is contracted by the pulling of the rod D with its head D. The metallic block or piston D lies Within and in contact With the metallic crosspiece B; hence the current passes from the wire S through Wire E, through the block or piston D, cross-piece B and wires A to the wire S. Now if a breakage Occurs in the Wire S the springe carries the head F and wire E back into the position shown in Fig. 3, and as the insulation g around the Wire E lies within the cross-piece B the wires A are completely insulated, thus rendering the broken portion of the Wire S'perfectly harmless.

This improvement, by doing away with the cylindrical box shown in the Letters Patent above referred to and employing the wires or rods A and cross-pieces B B', renders the in- IOO normally electrically intermediate wit-l1 said electric Wire and said rods or wires A and cross-pieces, a piston-rod E, head F, and spring H, and suitably-distributed insulating material, whereby when breakage of the Wire occurs the piston is withdrawn by the spring and the piston and rod or wire E insulated from the cross-pieces and Wires or rods A, substantially as-set forth.

MAX KERSTEIN. litnesses HENRY W. WILLIAMS, J. M. HARTNETT. 

